Optical lens

Abstract

The present invention provides an optical lens, which has a total of eight lenses. Along the optical axis from the object side to the imaging surface, it sequentially includes: a first lens with a negative optical power, whose object side is convex and whose image side is concave; a second lens with a negative optical power, whose object side is concave and whose image side is convex; a third lens with a positive optical power, whose object side and image side are both convex; a fourth lens with a negative optical power, whose object side is concave; a fifth lens with a positive optical power, whose image side is convex; a sixth lens with a positive optical power, whose object side and image side are both convex; a seventh lens with a negative optical power, whose object side and image side are both concave; an eighth lens with a positive optical power, whose object side is convex and whose image side is concave. The optical lens provided by the present invention has one or more advantages such as a large field of view, a large image surface, a large aperture, and high imaging quality through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and particularly to an optical lens. Background Art

[0002] With the continuous improvement of people's requirements for driving experience, in-vehicle application optical lenses are increasingly used in intelligent driving, and the status of in-vehicle optical lenses in the automotive-related industry is constantly rising.

[0003] Advanced Driver Assistance Systems (ADAS) play an important role in intelligent driving. It collects environmental information through various lenses and sensors to ensure the driving safety of the driver. In addition to requiring the optical lens to have a thin, light, short and small shape and have characteristics such as high pixels and high resolution, the existing ADAS system lenses also require the optical lens to be able to clearly image under low illuminance conditions. Therefore, it is necessary to develop an optical lens with good imaging effect. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide an optical lens, which has the advantage of excellent imaging quality.

[0005] The technical solution adopted by the present invention is as follows:

[0006] An optical lens, comprising a total of eight lenses, which successively include, along the optical axis from the object side to the imaging surface:

[0007] A first lens with negative optical power, the object side surface of which is convex and the image side surface of which is concave;

[0008] A second lens with negative optical power, the object side surface of which is concave and the image side surface of which is convex;

[0009] A third lens with positive optical power, both the object side surface and the image side surface of which are convex;

[0010] A fourth lens with negative optical power, the object side surface of which is concave;

[0011] A fifth lens with positive optical power, the image side surface of which is convex;

[0012] A sixth lens with positive optical power, both the object side surface and the image side surface of which are convex;

[0013] A seventh lens with negative optical power, both the object side surface and the image side surface of which are concave;

[0014] An eighth lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave;

[0015] Wherein, the radius of curvature R8 of the image side surface of the fourth lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 1.3 < (R8 - R9) / (R8 + R9) < 32.

[0016] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 10; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.5 < TTL / IH < 4.4.

[0017] Further preferably, the maximum field of view angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 84° < FOV / Fno < 89°; the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.5 < IH / EPD < 4.5.

[0018] Further preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 2 < IH / f < 2.5; the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.8 < BFL / f < 1.1.

[0019] Further preferably, the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20; the clear aperture diameter d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.5.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -25 < f4 / f < -6.5; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.7 < f5 / f < 6.5; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 2.5 < f5678 / f < 2.8.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2 < f7 / f < -1.2; the object side surface curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.9 < R13 / f < -1.3; the image side surface curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.7 < R14 / f < 6.1.

[0022] More preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 3.8 < f8 / f < 4.2; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < R16 / f < 17.

[0023] More preferably, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.8 < f4 / f5 < -1; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: -7 < R8 / R9 < -1.

[0024] More preferably, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.2 < (R13 - R14) / (R13 + R14) < -1.7; the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -1.5 < (R15 + R16) / (R15 - R16) < -1.2.

[0025] The optical lens provided by the present invention adopts eight lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as a large field of view, a large image plane, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 2 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 is the MTF curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 5 is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 6 It is the MTF curve graph of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 7 It is the structural schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0034] Figure 8 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 9 It is the MTF curve graph of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 10 It is the structural schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0037] Figure 11 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 4 of the present invention.

[0038] Figure 12 It is the MTF curve graph of the optical lens in Embodiment 4 of the present invention.

[0039] Figure 13 It is the structural schematic diagram of the optical lens in Embodiment 5 of the present invention.

[0040] Figure 14 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 5 of the present invention.

[0041] Figure 15 It is the MTF curve graph of the optical lens in Embodiment 5 of the present invention.

[0042] Figure 16 It is the structural schematic diagram of the optical lens in Embodiment 6 of the present invention.

[0043] Figure 17 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 6 of the present invention.

[0044] Figure 18 It is the MTF curve graph of the optical lens in Embodiment 6 of the present invention.

[0045] Figure 19 It is the structural schematic diagram of the optical lens in Embodiment 7 of the present invention.

[0046] Figure 20 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 7 of the present invention.

[0047] Figure 21 It is the MTF curve graph of the optical lens in Embodiment 7 of the present invention.

[0048] Figure 22 It is a schematic structural diagram of the optical lens in Embodiment 8 of the present invention.

[0049] Figure 23 It is the F-Tan(Theta) distortion curve of the optical lens in Embodiment 8 of the present invention.

[0050] Figure 24 It is the MTF curve graph of the optical lens in Embodiment 8 of the present invention.

[0051] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0052] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0053] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature and do not represent any limitation on the feature. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0054] In the drawings, for the sake of clarity, the thickness, size, and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0055] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0056] It should also be understood that the terms "comprise", "comprising", "have", "containing" and / or "containing" when used in this specification denote the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features rather than an individual element in the list. In addition, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0058] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0059] The optical lens provided by the embodiment of the present invention has a total of eight lenses, which are, in order from the object side to the imaging surface along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens.

[0060] In some embodiments, the first lens may have a negative optical power, its object side is convex, and its image side is concave. The second lens may have a negative optical power, its object side is concave, and its image side is convex. The third lens may have a positive optical power, and both its object side and image side are convex. The fourth lens may have a negative optical power, its object side is concave, and its image side may be concave or convex. The fifth lens may have a positive optical power, its object side may be concave or convex, and its image side is convex. The sixth lens may have a positive optical power, and both its object side and image side are convex. The seventh lens may have a negative optical power, and both its object side and image side are concave. The eighth lens may have a positive optical power, its object side is convex, and its image side is concave.

[0061] In some embodiments, the optical lens may further include a diaphragm, which may be located between the fourth lens and the fifth lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image. Additionally, when the diaphragm is located between the fourth lens and the fifth lens, the diaphragm can reasonably distribute the functions of the first lens to the eighth lens. For example, the first lens, the second lens, the third lens, and the fourth lens can be used to receive light to a greater extent, and the fifth lens to the eighth lens can be used to correct aberrations, which is beneficial to balancing the structure of the entire optical system. Furthermore, when the diaphragm is located between the fourth lens and the fifth lens, it is convenient to correct the diaphragm aberration.

[0062] In some embodiments, the optical lens may further include a filter, which is disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0063] In some embodiments, the sixth lens and the seventh lens may be glued together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0064] In some embodiments, the radius of curvature R8 of the image side surface of the fourth lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 1.3 < (R8 - R9) / (R8 + R9) < 32. Meeting the above range, by controlling the radii of curvature of the lenses before and after the diaphragm, the stray light of the optical lens can be effectively controlled, the formation of ghost images can be reduced, and the imaging quality of the optical lens can be improved. More specifically, 1.33 < (R8 - R9) / (R8 + R9) < 31.86.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 10. Meeting the above range can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens. More specifically, 8.1 < TTL / f < 9.96.

[0066] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.5 < TTL / IH < 4.4. Meeting the above range ensures that under the condition of the same total length of the lens, there is a larger image surface, which can match a larger-sized imaging chip to achieve high-definition imaging, and better achieve the balance between the small total length and the large image surface of the lens. More specifically, 3.58 < TTL / IH < 4.37.

[0067] In some embodiments, the maximum field of view (FOV) of the optical lens and the aperture value (Fno) of the optical lens satisfy: 84° < FOV / Fno < 89°. Meeting the above range defines that the optical lens has an appropriate field of view and aperture value, enabling it to collect light at large angles and obtain good imaging quality. More specifically, 84.2° < FOV / Fno < 88.25°.

[0068] In some embodiments, the true image height (IH) corresponding to the maximum field of view of the optical lens and the entrance pupil diameter (EPD) of the optical lens satisfy: 3.5 < IH / EPD < 4.5. Meeting the above range can increase the width of the light beam entering the optical lens, improving the brightness at the image plane of the optical lens and avoiding vignetting. More specifically, 3.65 < IH / EPD < 4.45.

[0069] In some embodiments, the true image height (IH) corresponding to the maximum field of view of the optical lens and the effective focal length (f) of the optical lens satisfy: 2 < IH / f < 2.5. Meeting the above range controls the image height and focal length of the optical lens within a reasonable range, which helps the optical lens have the characteristic of a large image plane and improves the imaging quality. More specifically, 2.14 < IH / f < 2.4.

[0070] In some embodiments, the effective focal length (f) of the optical lens and the back focal length (BFL) of the optical lens satisfy: 0.8 < BFL / f < 1.1. Meeting the above range defines that the optical lens has an appropriate back focus, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty. More specifically, 0.82 < BFL / f < 1.1.

[0071] In some embodiments, the total optical length (TTL) of the optical lens, the true image height (IH) corresponding to the maximum field of view of the optical lens, and the maximum field of view (FOV) of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20. Meeting the above range limits the length of the optical lens under the same imaging area and the same field of view, achieving miniaturization of the optical lens. More specifically, 16.15 < TTL / (IH / 2) / (FOV / 2)×180° < 19.65.

[0072] In some embodiments, the clear aperture diameter (d1) of the object side surface of the first lens, the true image height (IH) corresponding to the maximum field of view of the optical lens, and the maximum field of view (FOV) of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.5. Meeting the above range can have a small front aperture while meeting the requirements of the optical lens having a large field of view and a large image plane. More specifically, 0.27 < d1 / (IH / 2) / tan(FOV / 2) < 0.47.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -25 < f4 / f < -6.5. Meeting the above range and defining that the fourth lens has an appropriate negative optical power can diverge the light rays emitted by the third lens, making the light rays in the peripheral field of view show an upward trend, which is beneficial for the image points on the imaging surface to be away from the optical axis, so as to facilitate achieving the effect of matching with a large chip, obtaining a larger picture, effectively eliminating aberrations, and improving the resolution ability of the optical lens. More specifically, -24.75 < f4 / f < -6.81.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.7 < f5 / f < 6.5; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -3.9 < R10 / f < -2. Meeting the above range and setting the fifth lens to have a positive refractive power and a suitable surface shape is beneficial for converging light rays while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens. More specifically, 2.74 < f5 / f < 6.45; -3.85 < R10 / f < -2.01.

[0075] In some embodiments, the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens, and the eighth lens and the effective focal length f of the optical lens satisfy: 2.5 < f5678 / f < 2.8. Meeting the above range and reasonably setting the relationship of the lens group behind the aperture is beneficial for balancing various aberrations generated by the lens group in front of the aperture and improving the overall imaging quality. More specifically, 2.5 < f5678 / f < 2.77.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2 < f7 / f < -1.2; the radius of curvature R13 of the object side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -1.9 < R13 / f < -1.3; the radius of curvature R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: 2.7 < R14 / f < 6.1. Meeting the above range and setting the seventh lens to have a negative refractive power and a bi-concave surface shape can effectively balance various aberrations generated by the front lens group, and at the same time is beneficial for increasing the degree of divergence of light rays, increasing the area of light rays entering the imaging surface, realizing large target surface imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -1.93 < f7 / f < -1.24; -1.83 < R13 / f < -1.3; 2.72 < R14 / f < 6.02.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 3.8 < f8 / f < 4.2; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < R16 / f < 17. Meeting the above ranges and setting the eighth lens to have a positive refractive power and a suitable surface shape are conducive to light convergence, enabling the light path to smoothly transition to the rear, reducing the height of the light incident on the rear, slowing down the upward trend of the light, avoiding light energy loss caused by too large a chief ray angle between the large field-of-view light and the chip when reaching the imaging surface, facilitating the improvement of the illuminance of the edge field of view, and being conducive to achieving a short overall optical length. More specifically, 3.85 < f8 / f < 4.16; 1.65 < R15 / f < 1.85; 10.13 < R16 / f < 16.14.

[0078] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.8 < f4 / f5 < -1; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: -7 < R8 / R9 < -1. Meeting the above ranges is conducive to the smooth transition of light, conducive to correcting the aberration of the optical lens, and improving the imaging quality of the optical lens. More specifically, -8.77 < f4 / f5 < -1.05; -6.95 < R8 / R9 < -1.05.

[0079] In some embodiments, the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.2 < (R13 - R14) / (R13 + R14) < -1.7. Meeting the above range is conducive to increasing the area of light entering the imaging surface, achieving large-format imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -3.11 < (R13 - R14) / (R13 + R14) < -1.72.

[0080] In some embodiments, the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -1.5 < (R15 + R16) / (R15 - R16) < -1.2. Meeting the above range is conducive to suppressing the angle of the edge field of view incident on the imaging surface, effectively transmitting more light beams to the imaging surface, and at the same time being able to balance the field curvature and spherical aberration of the optical lens, and improving the imaging quality of the optical lens. More specifically, -1.42 < (R15 + R16) / (R15 - R16) < -1.23.

[0081] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis satisfy: 0.4 < ∑CT / TTL < 0.6. Satisfying the above range can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens. More specifically, 0.44 < ∑CT / TTL < 0.6.

[0082] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis and the effective focal length f of the optical lens satisfy: 4.6 < ΣCT / f < 6.5. Satisfying the above range can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens. More specifically, 4.64 < ΣCT / f < 6.42.

[0083] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.2 < f1 / f < -1.7. Satisfying the above range, by setting the first lens to have a negative refractive power, it is beneficial for the first lens to receive a larger angle of light and collect as much light as possible into the rear optical system, achieving a large field of view while increasing the light flux. More specifically, -2.15 < f1 / f < -1.75.

[0084] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -73 < f2 / f < -4.9. Satisfying the above range makes the second lens have a negative optical power and has the effect of diverging light. At the same field of view angle, it further diverges the light emerging from the image side of the first lens, and can disperse the central light and marginal light of each field of view, enabling the rear optical system to have a larger light receiving surface to receive the light emerging from the image side of the second lens, achieving a larger light input and being beneficial to increasing the relative illumination. More specifically, -72.57 < f2 / f < -4.91.

[0085] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.9 < f3 / f < 3.6. Satisfying the above range limits the third lens to have an appropriate positive optical power and has the effect of converging light, depressing the height of peripheral light, which is beneficial to reducing the aperture of the rear lens. More specifically, 2.94 < f3 / f < 3.6.

[0086] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 2 < f6 / f < 2.3; the radius of curvature R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 2 < R11 / f < 2.7. Satisfying the above ranges, defining that the sixth lens has a positive optical power and a suitable surface shape is conducive to light convergence. And by combining the sixth lens with a positive optical power and the seventh lens with a negative optical power, the optical path difference between different fields of view can be adjusted, the resolution can be improved, it is beneficial for light to enter the rear lens smoothly, and further the field curvature can be reduced and the off-axis aberration of the optical lens can be corrected. More specifically, 2.02 < f6 / f < 2.3; 2.07 < R11 / f < 2.64.

[0087] In some embodiments, the combined focal length f67 of the sixth lens and the seventh lens and the combined focal length f5678 of the fifth, sixth, seventh, and eighth lenses satisfy: -37 < f67 / f5678 < -1.5. Satisfying the above range and defining the focal length relationship between the cemented lens group and the lens group behind the aperture can effectively correct chromatic aberration, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens. More specifically, -36.36 < f67 / f5678 < -1.66.

[0088] In some embodiments, the optical lens satisfies the following conditional expressions: 4.6 mm < f < 5 mm; 140° < FOV < 170°; 2.5 mm < EPD < 3 mm; 39 mm < TTL < 49 mm; 1.6 < Fno < 2; 10 mm < IH < 12 mm; 18° < CRA < 21°; 3.9 mm < BFL < 5.5 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, FNO represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle of the optical lens, and BFL represents the back focal length of the optical lens. Satisfying the above ranges, the optical lens has at least one or more advantages such as a large image plane, a large aperture, and a large field of view angle. More specifically, 4.64 mm < f < 4.94 mm; 2.5 mm < EPD < 2.91 mm; 39.9 mm < TTL < 48.1 mm; 1.69 < Fno < 1.91; 18.15° < CRA < 20.05°; 3.96 mm < BFL < 5.41 mm; 149° < FOV < 161°; 10.62 mm < IH < 11.15 mm.

[0089] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0090] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical lens structure, the aspherical lens structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the second lens, the fifth lens, and the eighth lens of the present invention adopt aspherical lenses; the first lens, the third lens, the fourth lens, the sixth lens, and the seventh lens adopt spherical lenses.

[0091] In various embodiments of the present invention, when the lens adopts an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0092] ;

[0093] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0094] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are somewhat different. For specific differences, please refer to the parameter tables of each embodiment. The following embodiments are only the preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0095] Embodiment 1

[0096] Please refer to Figure 1 , which shows a schematic structural diagram of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 sequentially includes, along the optical axis from the object side to the imaging surface: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a diaphragm ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a filter G1.

[0097] Among them, the first lens L1 has a negative optical power, its object side S1 is convex, and its image side S2 is concave;

[0098] The second lens L2 has a negative optical power, its object side S3 is concave, and its image side S4 is convex;

[0099] The third lens L3 has a positive optical power, and both its object side S5 and image side S6 are convex;

[0100] The fourth lens L4 has a negative optical power, its object side S7 is concave, and its image side S8 is convex;

[0101] The fifth lens L5 has a positive optical power, its object side S9 is convex, and its image side S10 is convex;

[0102] The sixth lens L6 has a positive optical power, its object side S11 is convex, and its image side is convex;

[0103] The seventh lens L7 has a negative optical power, its object side is concave, and its image side S13 is concave;

[0104] The sixth lens L6 and the seventh lens L7 form a cemented lens group with a negative optical power, that is, the cemented surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S12;

[0105] The eighth lens L8 has a positive optical power, its object side S14 is convex, and its image side S15 is concave;

[0106] Both the object side S16 and the image side S17 of the filter are flat;

[0107] The imaging surface S18 is flat.

[0108] The second lens L2, the fifth lens L5, and the eighth lens L8 adopt glass aspherical lenses; the first lens L1, the third lens L3, the fourth lens L4, the sixth lens L6, and the seventh lens L7 adopt glass spherical lenses.

[0109] The relevant parameters of each lens in the optical lens 100 in Embodiment 1 are shown in Table 1.

[0110] Table 1

[0111]

[0112] The surface shape parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0113] Table 1-2

[0114]

[0115] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve diagram of the optical lens 100 are respectively as follows Figure 2 , Figure 3 shown.

[0116] Figure 2 shows the F-Tan(Theta) distortion curve of Embodiment 1, which represents the F-Tan(Theta) distortion of light rays with different wavelengths at different image heights on the imaging surface. The horizontal axis represents the F-Tan(Theta) distortion value (unit: %), and the vertical axis represents the semi-field angle (unit: °). It can be seen from the figure that the F-Tan(Theta) distortion of the optical lens is controlled within -75% to 0, indicating that the optical lens can correct distortion well.

[0117] Figure 3 shows the MTF (Modulation Transfer Function) curve diagram of Embodiment 1, which represents the modulation of the lens imaging at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value in this embodiment is above 0.3 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0118] Embodiment 2

[0119] Please refer to Figure 4 , which shows the structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0120] The relevant parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2.

[0121] Table 2

[0122]

[0123] The surface type parameters of the aspherical lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0124] Table 2-2

[0125]

[0126] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve diagram of the optical lens 200 are respectively as follows Figure 5 , Figure 6 shown. From Figure 5It can be seen that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. From Figure 6 It can be seen that the MTF value of this embodiment is above 0.38 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0127] Embodiment 3

[0128] Please refer to Figure 7 , which shows the structural schematic diagram of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0129] The relevant parameters of each lens in the optical lens 300 in Embodiment 3 are shown in Table 3.

[0130] Table 3

[0131]

[0132] The surface shape parameters of the aspherical lens of the optical lens 300 in Embodiment 3 are shown in Table 3-2.

[0133] Table 3-2

[0134]

[0135] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve diagram of the optical lens 300 are respectively as shown in Figure 8 , Figure 9 shown. It can be seen from Figure 8 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. It can be seen from Figure 9 that the MTF value of this embodiment is above 0.3 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0136] Embodiment 4

[0137] Please refer to Figure 10 , which shows the structural schematic diagram of the optical lens 400 provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0138] The relevant parameters of each lens in the optical lens 400 in Embodiment 4 are shown in Table 4.

[0139] Table 4

[0140]

[0141] The surface type parameters of the aspherical lens of the optical lens 400 in Embodiment 4 are shown in Table 4-2.

[0142] Table 4-2

[0143]

[0144] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve graph of the optical lens 400 are respectively as shown in Figure 11 、 Figure 12 shown. It can be seen from Figure 11 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. It can be seen from Figure 12 that the MTF value of this embodiment is above 0.3 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0145] Embodiment 5

[0146] Please refer to Figure 13 , which shows the structural schematic diagram of the optical lens 500 provided in Embodiment 5 of the present invention. Compared with Embodiment 1, the main differences are: the image side surface S8 of the fourth lens L4 is concave; the object side surface S9 of the fifth lens L5 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0147] The relevant parameters of each lens in the optical lens 500 in Embodiment 5 are shown in Table 5.

[0148] Table 5

[0149]

[0150] The surface type parameters of the aspherical lens of the optical lens 500 in Embodiment 5 are shown in Table 5-2.

[0151] Table 5-2

[0152]

[0153] In this embodiment, the F-Tan(Theta) distortion curve and MTF curve graph of the optical lens 500 are respectively as shown inFigure 14 , Figure 15 as shown. It can be seen from Figure 14 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. It can be seen from Figure 15 that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0154] Embodiment 6

[0155] Please refer to Figure 16 , which shows the structural schematic diagram of the optical lens 600 provided in Embodiment 6 of the present invention. Compared with Embodiment 1, the main differences are that: the image side surface S8 of the fourth lens L4 is a concave surface; the object side surface S9 of the fifth lens L5 is a concave surface; the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0156] The relevant parameters of each lens in the optical lens 600 in Embodiment 6 are shown in Table 6.

[0157] Table 6

[0158]

[0159] The aspheric lens surface type parameters of the optical lens 600 in Embodiment 6 are shown in Table 6-2.

[0160] Table 6-2

[0161]

[0162] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve diagram of the optical lens 600 are respectively as shown in Figure 17 , Figure 18 as shown. It can be seen from Figure 17 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. It can be seen from Figure 18 that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0163] Embodiment 7

[0164] Please refer to Figure 19, which shows the structural schematic diagram of the optical lens 700 provided in Embodiment 7 of the present invention. Compared with Embodiment 1, the main differences are as follows: the image side S8 of the fourth lens L4 is a concave surface; the object side S9 of the fifth lens L5 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0165] The relevant parameters of each lens in the optical lens 700 in Embodiment 7 are shown in Table 7.

[0166] Table 7

[0167]

[0168] The aspheric lens surface parameters of the optical lens 700 in Embodiment 7 are shown in Table 7-2.

[0169] Table 7-2

[0170]

[0171] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 700 are respectively as shown in Figure 20 , Figure 21 shown. It can be seen from Figure 20 that the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct the distortion well. It can be seen from Figure 21 that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0172] Embodiment 8

[0173] Please refer to Figure 22 , which shows the structural schematic diagram of the optical lens 800 provided in Embodiment 8 of the present invention. Compared with Embodiment 1, the main differences are as follows: the image side S8 of the fourth lens L4 is a concave surface; the object side S9 of the fifth lens L5 is a concave surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0174] The relevant parameters of each lens in the optical lens 800 in Embodiment 8 are shown in Table 8.

[0175] Table 8

[0176]

[0177] The aspheric lens surface parameters of the optical lens 800 in Embodiment 8 are shown in Table 8-2.

[0178] Table 8-2

[0179]

[0180] In this embodiment, the F-Tan(Theta) distortion curve and the MTF curve graph of the optical lens 800 are respectively as shown in Figure 23 and Figure 24 shown. As can be seen from Figure 23 , the F-Tan(Theta) distortion of the optical lens is controlled within -80% to 0, indicating that the optical lens can correct distortion well. As can be seen from Figure 24 , the MTF value of this embodiment is above 0.3 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve decreases uniformly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0181] Please refer to Table 9 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value Fno, the true image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, and the values corresponding to each conditional expression in each embodiment.

[0182] Table 9

[0183]

[0184] In summary of the above embodiments, the optical lens provided by the present invention uses eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as a large field of view angle, a large image plane, a large aperture, and high imaging quality.

[0185] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0186] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. An optical lens, with a total of eight lenses, characterized in that, From the object side to the imaging plane along the optical axis, it successively includes: A first lens with negative optical power, whose object side is convex and whose image side is concave; A second lens with negative optical power, whose object side is concave and whose image side is convex; A third lens with positive optical power, whose object side and image side are both convex; A fourth lens with negative optical power, whose object side is concave; A fifth lens with positive optical power, whose image side is convex; A sixth lens with positive optical power, whose object side and image side are both convex; A seventh lens with negative optical power, whose object side and image side are both concave; An eighth lens with positive optical power, whose object side is convex and whose image side is concave; Wherein, the curvature radius R8 of the image side of the fourth lens and the curvature radius R9 of the object side of the fifth lens satisfy: 1.3 < (R8 - R9) / (R8 + R9) < 32; The maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 84° < FOV / Fno < 89°; The true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.5 < IH / EPD < 4.

5.

2. The optical lens according to claim 1, wherein The overall length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 8 < TTL / f < 10; The overall length TTL of the optical lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 3.5 < TTL / IH < 4.

4.

3. The optical lens according to claim 1, characterized in that, The curvature radius R8 of the image side of the fourth lens and the curvature radius R9 of the object side of the fifth lens satisfy: 1.33 < (R8 - R9) / (R8 + R9) < 31.86; The maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 84.2° < FOV / Fno < 88.25°; The true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.65 < IH / EPD < 4.

45.

4. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2 < IH / f < 2.5; The effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.8 < BFL / f < 1.

1.

5. The optical lens according to claim 1, characterized in that, The overall length TTL of the optical lens, the true image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 16 < TTL / (IH / 2) / (FOV / 2)×180° < 20; The clear aperture d1 of the object side of the first lens, the true image height IH corresponding to the maximum field of view of the optical lens and the maximum field of view FOV of the optical lens satisfy: 0.25 < d1 / (IH / 2) / tan(FOV / 2) < 0.

5.

6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -25 < f4 / f < -6.5; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.7 < f5 / f < 6.5; the combined focal length f5678 of the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 2.5 < f5678 / f < 2.

8.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -2 < f7 / f < -1.2; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.9 < R13 / f < -1.3; the image-side curvature radius R14 of the seventh lens and the effective focal length f of the optical lens satisfy: 2.7 < R14 / f < 6.

1.

8. The optical lens according to claim 1, characterized in that The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 3.8 < f8 / f < 4.2; the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6 < R15 / f < 1.9; the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 10 < R16 / f < 17.

9. The optical lens according to claim 1, wherein The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -8.8 < f4 / f5 < -1; the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: -7 < R8 / R9 < -1.

10. The optical lens according to claim 1, wherein, The object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: -3.2 < (R13 - R14) / (R13 + R14) < -1.7; the object-side curvature radius R15 of the eighth lens and the image-side curvature radius R16 of the eighth lens satisfy: -1.5 < (R15 + R16) / (R15 - R16) < -1.2.

Images